110VAC-220VAC
I had one of these croak on me, was wondering why it died.
I had been running it on 120VDC (first half of my transistor magic smoke generator, err, inverter) and that was a suspect, turns out it wasn't.
Cracked it open with a vise, it split up very cleanly. It's a cheap 3-transistor optoisolator feedback design, trimmed by sticking in resistors in a parallel slot.
noted the output was shorted. Pulled secondary rectifier - short still there. Pulled out zener crowbar... short gone and zener was shorted! Checked switch transistor... okay. Filter caps...okay.
Replaced zener... working PSU once more.
What was interesting: it's a 12V PSU that measured 12.2V OCV. It had a 13V 1N4743A crowbar. Not much room for error...
Now comes the task of gluing the plastic back together. Ugh...
probably tape + zip tie...
I had one of these croak on me, was wondering why it died.
I had been running it on 120VDC (first half of my transistor magic smoke generator, err, inverter) and that was a suspect, turns out it wasn't.
Cracked it open with a vise, it split up very cleanly. It's a cheap 3-transistor optoisolator feedback design, trimmed by sticking in resistors in a parallel slot.
noted the output was shorted. Pulled secondary rectifier - short still there. Pulled out zener crowbar... short gone and zener was shorted! Checked switch transistor... okay. Filter caps...okay.
Replaced zener... working PSU once more.
What was interesting: it's a 12V PSU that measured 12.2V OCV. It had a 13V 1N4743A crowbar. Not much room for error...
Now comes the task of gluing the plastic back together. Ugh...
probably tape + zip tie...
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